Meet Our Veterinary Team

Man in a gray polo shirt with "GVS" logo standing in front of a building with brown and white siding.

Dr. John McDermott

Dr. John McDermott has been at the Granville Veterinary Service since 1988, before the practice evolved into a large animal ambulatory service. He has had an ownership position with the Granville Veterinary Service Large Animal practice since 1990. John focuses on reproductive service to both cattle and equine patients with neonatal, calf, foal, and maternal care an important extension of that work. Equine lameness, dentistry, and overall wellness are other critical aspects of his work. He has a special interest in assisting dairy farmers with their quality milk production goals, along with calf care and wellness protocols.

  • John received his DVM from the University of Florida College of Veterinary Medicine in 1988 following the completion of a Masters in Reproductive Physiology in 1984. John was raised in southeast Massachusetts where he was involved with 4-H and showing horses. He discovered his love of cattle while pursuing his bachelor's degree at Cornell University, and then worked at several dairy farms in New Jersey and Florida while on academic breaks.

    John and his wife Laura own and operate Seldom Still Farm, a small Thoroughbred breeding farm in Hebron, New York. They have four children and soon to be eight grandchildren.

A person standing next to a white donkey with a brown cow in the background, in a fenced pasture with a wooden barn.

Dr. Karalyn Lonngren

Dr. Karalyn Lonngren joined Granville Veterinary Service in 2021. She obtained her bachelor's and master's degrees from the University of Rhode Island where she conducted research on small ruminant parasitology. Parasite preventative strategies is still one of her favorite veterinary topics. She then received her Doctorate in Veterinary Medicine from the University of Pennsylvania where she focused on dairy and equine medicine. Her interests include small ruminant medicine and all aspects of large animal preventative medicine.

  • Karalyn grew up in Rhode Island as one of five siblings. She was active in 4-H, especially with her dairy goats, and was always looking for any opportunity to spend time around horses. Her introduction to production livestock occurred as a young adult when she spent several summers working on a cow-calf ranch in Montana.

    In her free time Karalyn enjoys outdoor activities and spending time with her animals.

Person in a uniform kneeling on a blue floor inside a stable, holding a small goat, with another goat standing nearby.

Dr. Jessica Jasenski

Dr. Jessica Jasenski became an Associate Veterinarian at Granville Veterinary Service in 2024. She loves to work with a variety of animals including cows, horses, sheep, goats, pigs, alpacas, and llamas. Jessica has an interest in preventative medicine such as dental work, vaccinations, and well-animal exams. Her favorite calls are for delivery assistance for sheep and goats. She has a passion to share her knowledge with the local community. Jessica enjoys the variety of her days and the unknown of what the day will bring.

  • Originally from Connecticut, Jessica found her love of farm animal medicine at the University of Maine while working with sheep, pigs, and cows, where she obtained a degree in Zoology and Pre-Medical Studies. She further honed her interests while working with the teaching animals at Midwestern University just outside of Phoenix, Arizona, where she received her DVM in 2024. There she deepened her connection and appreciation of cows and horses. After being away from the East Coast for a few years she knew she had to come back to practice equine and food animal medicine.

    Jessica is a fan of the outdoors (even winters) and loves to hike and swim. When the days are poor she is an avid reader at home with her two cats.

Administrative Team